Rotating impact sprinkler

ABSTRACT

A rotating impact sprinkler comprising a device for connecting the pressurized water column to a rotating joint which supports a rotating assembly which is formed by a tubular body with a nozzle for generating a jet, an oscillating arm and deflection element mounted at the end of the arm so as to interact with the jet. The deflection element comprises at least one main deflector which oscillates elastically in a direction which is transverse to the arm between a central equilibrium position, in which the surface effected by the jet is minimal, and at least one lateral abutment position, in which the surface effected by the jet is maximal. The change from the minimally effected surface to the maximal one is sudden, so as to instantly increase withdrawal of energy from the jet and generate impulsive forces on the deflector.

The present invention relates to a rotating impact sprinkler of the typeused to perform irrigation on an entire circumference or on partialsectors.

Known impact sprinklers of this type are generally placed on trolleys orsupporting frames and comprise means for connecting a pressurized watercolumn to a rotating joint, which in turn supports an assembly whichrotates about the axis of said joint. Said assembly is essentiallyformed by a tubular body which has, at one open end, an adapted nozzlefor generating a jet which is inclined with respect to the axis ofrotation of the assembly. Propulsion and jetbreaking means are mountedon the tubular body and are generally constituted by one or more armswhich oscillate about an axis which is substantially perpendicular tothe axis of rotation of the assembly and have one end suitable forperiodically interacting with the jet. At said end affected by the jet,each oscillating arm is provided with one or more deflectors suitablefor partially deflecting the jet, generating reaction forces which havecomponents which are parallel and perpendicular to the axis of rotationof the assembly and cause a periodic oscillation of the arm and astepwise rotary motion of the entire assembly.

In order to prevent the uncontrolled rotation of the assembly inexcessively large incremental steps, which would not allow an effectiveirrigation, appropriate braking means are inserted in the rotation jointwhich supports the assembly and are intended to contrast the rotation ofsaid assembly about its own main axis.

In order to perform irrigation on a limited angular sector it isnecessary to periodically reverse the direction of rotation of thesprinkler about its main axis. Automatic mechanisms are normallyprovided for this purpose and are suitable for varying the angle ofrelative incidence of the deflector with respect to the jet, so as toreverse the direction of the reaction forces which act on the assemblyin a direction which is perpendicular to its rotation axis. Saidmechanisms are generally actuated by stroke limit abutments which can bearranged on the fixed part of the rotating joint at the ends of theirrigation sector.

An essential requirement for sprinklers of the above described type isthat the rotation rate of the rotating assembly must be approximatelyconstant as the pressure and flow-rate of the jet and the attitude ofthe sprinkler vary. In fact, if the axis of rotation of the sprinkler isinclined with respect to the vertical, the components of the reactionforces and of the braking forces may vary, altering the rotation rate ofthe sprinkler, with consequent modifications and non-uniformities in theirrigation conditions. Some sprinklers of the above described type areknown which satisfactorily perform their task; DE-B-1151145, forexample, discloses a sprinkler having a deflector member mounted on arocking arm provided with a balance weight. These sprinklers, however,can be improved so as to eliminate some acknowledged disadvantages.

One of these disadvantages is constituted by the substantialnon-uniformity in the operation of sprinklers at low water feedpressures, which become increasingly necessary in order to reducefacility management costs and in general to limit energy consumption.This non-uniformity in operation is furthermore always present in theinitial startup step, since in practical use the pressure of the feedwater must be increased gradually, passing from a minimum value to amaximum one. During this transient, the propulsion arm of the sprinkler,which is initially motionless, starts to oscillate with a limitedfrequency and extent which increase gradually up to the steady-statevalues. Correspondingly, the interruptions of the jet are initially nilor minimal and increase progressively until they become complete andconstant. Now, if the sprinkler is not designed correctly, thistransient condition can last for an excessively long and sometimesindefinite time, with the consequence that the jet is not interruptedand digs a hole in the ground, irreparably damaging the crops.

A further disadvantage of known sprinklers consists of the fact that theintervals for the adjustment of the oscillation frequency and of therotation rate of the assembly are rather limited, unless the balancingof the oscillating arms is changed. In order to perform this operation,devices for modifying the position of the counterweights arranged on thearm are generally provided, but these mechanisms are very complicatedand require the use of special tools or of universal implements whichare not normally available in the place where the sprinkler is used.

The aim of the present invention is to overcome the disadvantagesdescribed above by providing an impact sprinkler which, by virtue of itscharacteristics of functionality and reliability, operates effectivelyand correctly in any operating and adjustment condition, even withextremely low feed pressures, as currently required in order to limitenergy consumption.

A further object of the present invention is to provide an impactsprinkler which maintains a substantially constant rotation rate as thepressure and flow-rate of the water vary and as the inclination of theground varies, even with considerable slope angles.

Another object of the present invention is to provide an impactsprinkler which achieves a self-limited energy withdrawal, i.e. whichdraws from the jet an amount of energy for propulsion which is inverselyproportional to the total energy of the jet, so as to ensure regularoperation in all conditions.

Another object of the present invention is to provide an impactsprinkler which has an adjustable rotation rate, by virtue of meansmounted directly on the sprinkler, without requiring any furtherexternal equipment.

Another object of the present invention is to provide a substantiallysimple sprinkler which can be used by personnel having no particularknowledge of sprinklers and is such as to require very littlemaintenance, so as to be advantageous from a merely economical point ofview.

This aim, these objects and others which will become apparenthereinafter are achieved by a rotating impact sprinkler of the typedescribed in the introductory part.

Further characteristics and advantages of the invention will becomeapparent from the description of a preferred but not exclusiveembodiment of the impact sprinkler according to the invention,illustrated only by way of non-limitative example in the accompanyingdrawings, wherein:

FIG. 1 is a general perspective view of the sprinkler according to theinvention;

FIG. 2 is a lateral general view of the sprinkler of FIG. 1;

FIG. 3 is a general top view of the sprinkler of FIG. 1;

FIG. 4 is a perspective view of a detail of the sprinkler according tothe invention;

FIG. 5 is a top view of the detail of FIG. 4;

FIG. 6 is a sectional side view of the detail of FIG. 5, taken along avertical plane indicated by VI--VI;

FIG. 7 is a rear view of the detail of FIG. 5;

FIG. 8 is a partially sectional schematic view of a detail of FIG. 2 ina first extreme position, taken along the plane indicated by VIII--VIII;

FIG. 9 is the same schematic view as FIG. 8 with the device in a secondextreme position;

FIG. 10 is a partially enlarged sectional view of another detail of thesprinkler according to the invention, taken along a vertical plane whichpasses through the axis of rotation of the assembly.

With reference to the above figures, the impact sprinkler according tothe invention, generally indicated by the reference numeral 1, isconnected by means of a connecting element 2 to a pipe 3 for feedingpressurized water. A rotating joint or bearing, generally indicated bythe reference numeral 4, is fixed on the connecting element 2 andcomprises a fixed lower portion 5, which is bolted to the element 2, andan upper movable portion 6, which supports a rotating assembly generallyindicated by the reference numeral 7. The rotation axis a of the joint4, which is approximately but not necessarily vertical, determines therotation axis of the assembly 7.

The assembly 7 comprises a tubular body or barrel 8 which is connectedto the upper portion 6 of the joint 4 by means of an elbow coupling 9,which has an angle θ between the outlet and the inlet so as to inclinethe barrel 8 with respect to the vertical, and a substantiallycylindrical connecting stub pipe 10. A nozzle or nosepiece 12 is fixedto the tubular body 8 at its end portion by means of a ring 11 or thelike and has an adapted profile and internal diameter so as to obtain ajet with a preset flow-rate and range according to the pressure of thewater.

A support 13 is disposed on the tubular body 8 at the nozzle 12 and has,at one end, a cylindrical seat 14 which defines a longitudinal axis bwhich is substantially parallel to the axis of the tubular body 8 and isspaced therefrom by a center distance A indicated in FIGS. 8 and 9.

A shaft, not illustrated in the drawings, can freely rotate in thecylindrical seat 14; a spider 15 is keyed thereon and defines a tubularmedian portion 16 and a head 17 with an axis c which is substantiallyperpendicular to the axis b of the seat 14.

An oscillating arm 20 is pivoted on the head 17 and, in an exemplifyingform illustrated in the drawings, is constituted by an approximatelyrectangular frame which is formed by two lateral members 21, 22,arranged on opposite sides with respect to the barrel 8, which arerigidly connected to one another by a rear cross-member 23 and by afront plate 24. The arm may pivot by means of a pair of lateral supports25, 26 which are crossed by a single axle or by lateral pivots 27.Initially, the arm 20 is in a substantially horizontal position, withthe cross-member 23 lowered so as to abut on the tubular body 8 and withits oscillation axis c inclined laterally, as illustrated in FIGS. 2, 3,8 and 9. In order to keep the arm in this equilibrium position,regardless of the inclination of the rotation axis a with respect to theground, and to furthermore allow to adjust the oscillation frequency ofthe arm, there are first return means, which exert on said arm a torquewhich is counter-clockwise in FIG. 2. Said return means can be of theelastic type, for example formed by a helical spring 28 which ispartially enclosed between two opposite cylindrical bushes 29, 30; thefirst bush is rigidly associated with the member 21 of the arm 20, thesecond one is rigidly associated with the head 17 of the support 15. Anend of the spring 28, which is not visible in the drawings, is fixed tothe bush 30, and the other end 31, which extends radially with respectto the axis c, is adjustably associated with the bush 29. For thispurpose, the bush 29 has a planar radial extension 32 shaped like acircular sector, with a cylindrical edge 33 which has angularly offsetseats 34 in which the radial end 31 of the spring 28 can be engaged.Thus, by selectively placing the end 31 of the spring in the variouscavities 34 of the edge 33 of the planar extension 32, it is possible toadjust the intensity of the return torque on the arm 20, with the effectof altering the extent and frequency of abutment thereof. The abovedescribed elastic return means can furthermore be coupled toeccentric-mass return means which can move along said arm in order toadjust the return torque.

Advantageously, a main deflector 40 is arranged on the plate 24 at adistance B from the nozzle 12 in equilibrium conditions so as toperiodically interact with the jet G. In this step, the jet exertshydrodynamic reaction forces on said deflector and is furthermoreinterrupted and broken up.

The deflector 40 may comprise an elongated body 41, having anapproximately triangular plan shape, with its vertex pivoted to theplate 24 by means of a pivot 42 with an axis d which is substantiallyperpendicular to said plate. The body 41 can thus rotate transversely tothe longitudinal direction of the arm 20 in a plane which issubstantially parallel to its oscillation axis c. At its end which isopposite to the pivoting end, the elongated body 41 has a prism-shapedexpanded portion 43 which defines a support for a deflection structure50 which will be described in detail hereinafter.

Second return means are conveniently provided for keeping the deflector40 in a central position aligned with the longitudinal direction of thearm. An exemplifying embodiment of said second return means may consistof a pair of longitudinal elastic laminas 44, 45 which are retained by acentral base 46 anchored on the supporting plate 24 and act on oppositesides on a central pivot 47 which is fixed below the prism-shapedexpanded portion 43. Lateral stroke limit abutments 48, 49,schematically indicated in FIG. 5 and intended to limit the oscillationangles α1 and α2 of the deflector 40 on one side and the other withrespect to the central equilibrium position, can furthermore beconveniently provided on the plate 24. The angles α1 and α2 can beidentical or, optionally, different so as to differentiate the rotationrate in the two directions. The deflector 40 can thus oscillateelastically about its central equilibrium position toward and away fromtwo lateral external abutment positions.

The structure 50 substantially comprises a pair of lateral deflectionsurfaces 51, 52 which converge and are substantially symmetrical withrespect to a longitudinal plane of the deflector which passes throughthe axis d, so as to form an angle β between them and an angle Γ withrespect to the oscillation plane of the deflector. The latter angle isnecessary in order to facilitate the gradual conveyance of the waterwithout causing a sudden flow-back of the jet. The angle β canfurthermore be greater or smaller than 180°, so that the overall shapeof the deflection structure 50 is wedge-like, respectively concave orconvex.

In each of the lateral deflection surfaces 51, 52 it is possible toidentify a first innermost or median portion 53, which has a certainfront cross-section with respect to the jet, and a second outermostportion 54, which has a larger front cross-section than said firstportion.

Experimentally, it has been possible to verify that optimum values ofthe angles α1 and α2 can be comprised between 5° and 30° and arepreferably equal to approximately 15°. The angle β can be comprisedbetween 60° and 270° and is preferably equal to approximately 130°. Theangle Γ can be comprised between 20° and 150° and is preferably equal toapproximately 60°. This last angle furthermore functionally depends onthe value of the center distance A, which can vary between 0 and 120 mmand is preferably equal to 60 mm. The value of B is not binding, and canbe determined from the other parameters and from the length of thedeflector 40.

Conveniently, according to the invention, the median portions 53 of eachdeflection surface 51, 52 are arranged so as to be affected by the jetwhen the deflector is in its approximately central position, whereas theouter portions 54 are affected by the jet when the deflector isproximate to one of its lateral abutment positions, on one side or onthe other with respect to the central position. In order to align thejet with only one of the lateral deflection surfaces 51, 52, the axis cof oscillation of the arm is alternatively inclined by angles o1 and o2,performing, corresponding rotations of the support 15, as described indetail hereinafter.

Advantageously, the front surface of the median portions 53 of thedeflection surfaces 51, 52 has such dimensions that the force F1generated by the jet is sufficient to overcome the contrast force of thesecond return means which act on the deflector, causing their rotationon the side opposite to the side of the portion affected by the jet,even for very low values of the energy of said jet. Said force F1,however, is smaller than the return force of the first elastic meanswhich act on the arm; said arm, in this step, is therefore kept in itsidle position and in any case does not start to oscillate yet.

The force F1, however, moves the deflector away from its centralposition, so as to expose to the jet one of its lateral portions 54,which has such dimensions as to produce on the arm a force F2 which isgreater than the return force, which causes the movement of the arm awayfrom its idle position.

The increase in the front cross-section from the minimum value to themaximum one is furthermore sudden, i.e. discontinuous and notprogressive, so that the forces generated on the arm are impulsive, witha peak value which ensures, in any case and with any attitude of thesprinkler, the beginning of the oscillation of the arm, preventingpossible instability situations.

This configuration is clearly visible in FIG. 7, wherein it can be seenthat the edge of the structure 50, seen frontally, is suddenly depressedand forms, in the central region defined by the inner portions 53, astep with respect to the upper edge of the outer portions 54.

In order to further reduce the risk of instability, the upper edges ofthe lateral portions 54 have planar or slightly curved surfaces 55 withan inclination suitable for partially deflecting the jet upward at thebeginning of interaction, generating a reaction force which is directeddownward and imposes an impulsive oscillation torque to the arm.

Two conveyance fins 56 are furthermore provided proximate to the lateraledges of the surfaces 54 and have lower deflection surfaces directedoutward and downward.

A channeling element 57 is conveniently arranged on the edge of theprism-shaped expanded portion 43 which is further backward with respectto the direction of the jet; its height is less than that of thedeflection structure 50, and it faces said structure so as to define,together with the deflection surfaces 51, 52, two connected collectionchannels 58, 59 which diverge outward and have open ends. Operatively,the water of the jet which wets the surfaces 51, 52 is deflecteddownward and is collected in the channels 58, 59 so as to be directedoutward and forward with respect to the jet.

The sprinkler according to the invention has means for reversing thedirection of rotation of the rotating assembly 7 after covering a presetangle. For this purpose, an approximately Z-shaped bracket 60 is pivotedon the oscillation axis b and has a longitudinal portion which isadjacent to the seat 14 of the support 13. An elongated nut 62 isdefined at the rear transverse end 61 of the bracket 60 and retains anactuation rod 64 by means of a stop screw 63. The free end 65 of the rod64 is conveniently shaped so as to be able to interact with two radialstroke limit protrusions, constituted for example by the folded ends oftwo open rings 66, 67 which are rigidly associated with the fixed lowerportion 5 of the joint 4.

The front transverse end 68 of the bracket 60 faces a transverse plate69 of the spider 15 and is connected thereto by means of an elasticconnecting rod 70. Said connecting rod 70 is pivoted to the plate 69 bymeans of a pivot 71 and is articulated to the front portion 68 of thebracket 60 by means of a pivot 72 which can move longitudinally alongthe connecting rod 70 and in contrast with a spring 70'. By virtue ofthis arrangement, the mechanical connection between the bracket 60 andthe spider 15 is elastic and is such as to cause the relative rotationof the two elements in opposite directions and with a snap-actionmovement, so as to occupy two mutually spaced positions.

By virtue of this arrangement, the axis of the head 17 of the support16, and therefore the oscillation axis c of the arm 20, are caused toselectively occupy two positions which are inclined on opposite sideswith respect to a substantially vertical plane, due to the interactionof the end 65 of the actuation rod 64 with the fixed abutments 66, 67,which are angularly offset with respect to the main rotation axis a ofthe sprinkler. Two stroke limit blocks 73, 74 are defined on theopposite ends of the bracket 13 in order to delimit the angles o1 and o2of inclination of the spider 15 and consequently of the oscillation axisc of the arm 20; the abutments 75, 76 of the plate 69 and the abutments77, 78 of the rear end 66 of the bracket 60 abut against said blocks 73,74 respectively, as illustrated in FIGS. 8 and 9.

The operation of the sprinkler is substantially apparent from what hasbeen described above.

Initially, the oscillation axis c of the jet is inclined to one side byan angle o1 or o2, arranging one of the lateral deflection surfaces 51,52 of the main deflector 40 in a position for interacting with the jet.Said jet initially affects the central portion 53 of one of thedeflection surfaces of the deflector, causing the rotation thereof aboutits axis d toward a lateral abutment position. Following this rotationof the deflector, the jet strikes the outer portion 54 and the upperedge 55 of the deflection surface of the deflector, with an instantincrease in front cross-section, generating a sudden impulsive forcewith both vertical and horizontal components which are more thansufficient to cause both the oscillation of the arm and the incrementalrotation of the assembly, regardless of the value of the energy of thejet.

After the assembly 7 has performed a preset rotation about the axis a,the motion reversal mechanism acts on the oscillation axis c of the arm20 so as to incline, on the side opposite to the initial one, andorientate the other one of the lateral surfaces 51, 52 so as to causethe rotation of the deflector and of the assembly in the directionopposite to the initial one.

FIG. 10 illustrates a self-adjusting brake structure, generallyindicated by the reference numeral 100, particularly but not exclusivelyintended for use for the impact sprinkler according to the invention.The connecting element 2 fixed to the water feed pipe 3 can be of theflanged type or of the type with an inner thread, made of brass or ofanother equivalent material, and is anchored to a torus-like body 101made of aluminum or the like, with a tapered internal surface which isconnected to the connecting element 2.

A pair of braking disks 102, 102' made of stainless steel are arrangedon the torus-like body 101; said disks have planar portions 103, 103'and inner and outer cylindrical annular portions, respectively 104, 104'and 105, 105'. The braking disks, the torus-like body and the flange aremutually rigidly coupled by means of bolts 106 or the like so as todefine, as a whole, a stationary or fixed portion 5 of the joint.

In the upper portion of the figure, the elbow coupling 9 is fixed bymeans of bolts 107 to a cover 108 which has a planar portion 109 and acylindrical tubular portion 110 with an internal diameter which is equalto that of the torus-like body 101.

The cover 108 is in turn anchored to a bottom 111 with a cylindricallateral portion 112 and a planar portion 113. On the respective planarportions 109 and 113, which face the planar surfaces 103, 103' of thebraking disks 102, 102', the cover 108 and the bottom 111 haverespective series of cylindrical cavities 114, 114' which are angularlyspaced. Two braking rings 120, 120' are interposed between the disks andthe planar walls of the cover and of the bottom; said rings are made ofwearproof synthetic material and have cylindrical protrusions or dowels121, 121' which engage in the respective cavities 114, 114', so as toensure the traction of the rings 120, 120' by the rotating portion ofthe joint. Helical springs 130 are furthermore provided in the cavities114 for the dowels 121 of the upper ring 120 and exert on the upperbraking ring 120 a compression force against the upper disk 102.

The assembly constituted by the elbow coupling 9, the cover 108, thebottom 111 and the braking rings 120, 120' constitutes the rotating partof the joint. By virtue of the hydraulic pressure, said rotating part ispushed upward, forcing the lower ring 120' against the lower disk 102'with a pressure which is proportional to that of the water. The frictionbetween the upper ring 120 and the upper disk 102 is instead alwaysensured by the compression force of the springs 130, which operate evenwith low pressures and regardless of the attitude of the sprinkler.

Conveniently, according to the invention, the angle of incidence θ andthe configuration of the elbow coupling 9 are preset so that the line ofaction of the reaction force R generated by the jet on the barrel isdirected substantially toward the region of contact of the rings and ofthe disks and also acts on the cylindrical lateral surfaces of theseelements.

The simultaneous presence of all these forces ensures that the brakingaction on the joint is self-adjusted and substantially proportional tothe pressure of the water as well as to the composition of the reactionforces which act on the sprinkler, achieving one of the essentialobjects of the invention.

It is furthermore noted that the line of action of the resultant of thereaction forces R on the joint 6 has the minimum lever arm allowed bythe geometry of the system, producing an overturning torque which iscentered in an axial region of the joint, with consequent minimalstresses and local deformations of said gaskets.

The sprinkler and the rotating joint thus conceived are susceptible tonumerous modifications and variations, all of which are within the scopeof the inventive concept expressed by the accompanying claims; all thedetails may furthermore be replaced with technically equivalentelements. By way of example, the oscillating arm, instead of beingconstituted by a frame in a central position, can be constituted by asingle elongated body pivoted laterally to the barrel. Similarly, themain deflector, instead of having a pair of lateral surfaces, may haveonly one of said surfaces, suitable for causing stepwise rotation in asingle direction; its pivoting axis may furthermore be arranged forwardor backward with respect to the deflection structure. Moreover, thebraking rings inserted in the rotating joint can be executed in aplurality of separate segments instead of in a monolithic structure.

I claim:
 1. A rotating impact sprinkler, comprising means for connectionto a pressurized water pipe, a rotating joint associated with saidconnecting means to support an assembly which can rotate about a firstaxis, said assembly being formed by a tubular body with an inlet and anoutlet, a nozzle arranged at the outlet of said body to generate a jet,braking means arranged inside said joint to contrast the rotation ofsaid assembly in a controlled manner, an oscillating arm which ispivoted to said body about a second oscillation axis which issubstantially perpendicular to the first axis, deflection means whichare mounted at one end of said arm in such a position to periodicallyinteract with the jet to break it and draw at least part of its energy,first return means for returning said oscillating arm toward a positionin which it interacts with said jet, the improvement consisting inthatsaid deflection means comprises a deflector which can elasticallymove with respect to the arm in a direction which is transverse to thelongitudinal extension thereof so as to periodically oscillate between asubstantially central equilibrium position in which the surface of thedeflector partially intersecting the jet has a front cross-section whichis minimal, and at least one lateral abutment position in which thesurface of the deflector partially intersecting the jet has a frontcross-section which is maximal, the variation in front cross-section inpassing from said minimal value to said maximal value at eachoscillation of the deflector being sudden so as to instantaneouslyincrease the withdrawal of energy from the jet and generate impulsiveforces on the deflector and consequently on the arm regardless of thejet's energy.
 2. The sprinkler according to claim 1, further including asecond return means which tends to keep said deflector in saidsubstantially central position to contrast its movement toward a lateralabutment position on one side or on the other with respect to saidsubstantially central position.
 3. The sprinkler according to claim 2,wherein said second return means comprises a pair of longitudinalelastic laminas which are rigidly associated with a plate forming asupport for said deflector and act on opposite sides on a central pivotwhich is fixed below an end of said body which forms the base for saidmonolithic deflection structure.
 4. The sprinkler according to claim 1,wherein the oscillation direction of said deflector is substantiallyparallel to a plane which is parallel to said arm and passes through itsoscillation axis (c).
 5. The sprinkler according to claim 4, whereinsaid deflector comprises at least one deflection surface which has anangle of inclination (Γ) with respect to the plane of oscillation of thedeflector so as to determine reaction forces having components which aresubstantially perpendicular and parallel to the oscillation axis of thearm.
 6. The sprinkler according to claim 5, wherein said at least onedeflection surface of the deflector comprises at least one firstdeflection portion and at least one second deflection portion which aremutually adjacent and are intended to be struck by the jet when saiddeflector is respectively in said central position and in said at leastone lateral abutment position.
 7. The sprinkler according to claim 6,wherein a front cross-section of a first deflection portion has suchdimensions as to in any case draw from the jet an amount of energy whichis sufficient to progressively move the deflector away from its centralposition toward a lateral abutment position, converting said energy intoa force (F1) which is greater than the contrast force of a second returnmeans.
 8. The sprinkler according to claim 6, wherein a frontcross-section of said second portion has such dimensions as to draw fromthe jet an amount of energy which is sufficient to determine theinstantaneous oscillation of the arm and the rotation of the assemblywith preset extent and abutment frequency, converting said energy into aforce (F2) which is greater than the contrast force of said first returnmeans.
 9. The sprinkler according to claim 8, wherein said deflector isrotatably mounted on said arm so as to oscillate about a third axis (d)which is substantially perpendicular to the second axis (c) with presetangular strokes (α1, α2) with respect to said central position which issubstantially aligned with the arm.
 10. The sprinkler according to claim9, wherein said deflector comprises a substantially elongated main bodywhich has one end pivoted to said arm, the other end forming asupporting base for a monolithic deflection structure as substantiallydefined by said at least one deflection surface.
 11. The sprinkleraccording to claim 10, wherein said monolithic deflection structurecomprises a pair of deflection surfaces which are mutually adjacent, areinclined by a preset angle (β) and are substantially symmetrical withrespect to the longitudinal axis of said body, with said at least onefirst portion arranged inward and said at least one second portionarranged outward, so as to define a substantially wedge-shapedstructure.
 12. The sprinkler according to claim 1, wherein said arm isdefined by a substantially elongated frame which is formed by at leastone lateral member which defines a rear cross-member and a front platewhich forms a support for said main deflector.
 13. The sprinkleraccording to claim 12, further including a second return means whichtends to keep said deflector in said substantially central position,said second return means comprising a pair of longitudinal elasticlaminas which are rigidly associated with said plate and act on oppositesides on a central pivot which is fixed below the end of said body whichforms the base for said monolithic deflection structure.
 14. accordingto claim 11, wherein the angle of inclination (Γ) of said two deflectionsurfaces with respect to the plane of oscillation of the deflector is afunction of said center distance (A), said angle of inclination isapproximately 60°.
 15. The sprinkler according to claim 11, wherein saidpreset angle (β) is between 60° and 270°.
 16. The sprinkler according toclaim 15, wherein said preset angle is approximately 130°.
 17. Thesprinkler according to claim 11, wherein each of said deflectionsurfaces furthermore comprises, at said at least one second portions, anupper edge inclined upward so as to impart to said arm a furtherdownward force which tends to eliminate any risk of instability.
 18. Thesprinkler according to claim 17, further including a pair of conveyanceelements which are arranged proximate to lateral edges of said secondportion, said conveyance elements having lower conveyance surfaces whichare inclined downward.
 19. The sprinkler according to claim 18, whereinsaid monolithic deflection structure includes a channeling element whichfaces a base of said deflection surfaces so as to form a pair ofcollection channels which are directed downward and outward.
 20. Thesprinkler according to claim 1, wherein said oscillation axis (c) ofsaid arm is defined by a transverse portion of a spider-shaped supportwhich has a longitudinal portion which can rotate about a fourth axis(b) which is substantially parallel to a longitudinal axis of saidtubular body and has a preset center distance (A) with respect to saidtubular body.
 21. The sprinkler according to claim 20, wherein saidcenter distance (A) is between 0 and 120 mm.
 22. The sprinkler accordingto claim 20, wherein said first return means comprises a helical torsionspring which has one end rigidly fixed to a head of said spider shapedsupport and a second end which is selectively engageable in a series ofseats defined in angularly offset positions of a bush which is rigidlyassociated with said arm, so as to vary the contrast force which acts onthe latter.
 23. The sprinkler according to claim 20, further includingmeans for reversing the direction of rotation of the assembly, saidreversal means comprising a bracket which has one end pivoted to saidfourth axis of rotation (b) of said spider-shaped support.
 24. Thesprinkler according to claim 23, wherein an actuation rod is rigidlyfixed at an end of said bracket which is opposite to the pivoting end,said rod having a free end which is suitable for engaging a pair ofangular abutments which are rigidly associated with a fixed portion ofsaid joint, so as to cause the rotation of said spider-shaped supportand consequently of said axis of oscillation (c) of the arm by a presetangle on one side (o1) or on the other side (o2) with respect to asubstantially vertical plane, so as to correspondingly expose a surfaceof said deflector.
 25. The sprinkler according to claim 20, wherein saidcenter distance is approximately 60 mm.
 26. The sprinkler according toclaim 20, wherein the angle of inclination (Γ) of said deflector surfacewith respect to the plane of oscillation of the deflector is a functionof said center distance (A), said angle of inclination is approximately60°.
 27. A rotating impact sprinkler, comprising: means for connectionto a pressurized water pipe;a rotating joint associated with saidconnecting means to support an assembly which can rotate about a firstaxis, said assembly being formed by: a tubular body with an inlet and anoutlet; said rotating joint having a fixed lower portion which iscoupled to said pressurized water pipe and a movable upper portion whichis coupled to said tubular body by means of at least one elbow coupling;a nozzle arranged at the outlet of said body to generate a jet; brakingmeans arranged inside said joint to contrast the rotation of saidassembly in a controlled manner; said braking means having a pair ofopposite disks which are rigidly fixed to said fixed lower portion and apair of braking rings which are rigidly associated with said movableupper portion and act on said disks on opposite sides thereof; anoscillating arm which is pivoted transversely to said body about asecond oscillation axis which is substantially perpendicular to thefirst axis; deflection means which are mounted at one end of said arm insuch a position as to periodically interact with the jet to break it anddraw at least part of its energy; first return means for returning saidarm toward a position in which it interacts with said jet; and saiddeflection means comprise a deflector which can move in a directionwhich is transverse to said arm so as to oscillate elastically between asubstantially central equilibrium position, in which a surface of thedeflector which is struck by the jet is minimal, and at least onelateral abutment position, in which the surface of the deflectoraffected by the jet is maximal, the variation in the surfacecross-section in passing from said minimal value to said maximal valuebeing sudden so as to instantaneously increase the withdrawal of energyfrom the jet and generate impulsive forces on the deflector regardlessof the jet's energy.
 28. The sprinkler according to claim 27, whereinsaid disks have a substantially U-shaped radial cross-section, with aplanar annular portion and a pair of cylindrical edges.
 29. Thesprinkler according to claim 27, wherein said braking rings are definedby annular bodies which have a series of substantially cylindricalangularly spaced pivots arranged on one of their planar faces andintended to be accommodated in corresponding cavities defined in saidmovable upper portion to be pulled along by the rotation of said movableupper portion.
 30. The sprinkler according to claim 29, wherein saidmovable upper portion comprises an upper cover and a bottom, elasticmeans being arranged between said cover and an upper braking ring, saidelastic means being suitable for compressing said upper ring against therespective disk.
 31. The sprinkler according to claim 30, wherein one ofsaid braking rings is rigidly associated with said bottom so that thepressure exerted by the water on an inner surface of said movable upperportion determines a proportional thrust on said one of said brakingrings.
 32. The sprinkler according to claim 30, wherein said at leastone elbow coupling has an inclination angle (θ) that the line of actionof the resultant (R) of the reaction forces exerted by the body on saidcoupling is substantially directed toward the surfaces of mutual contactbetween said braking rings and said disks so as to increase the brakingaction proportionally to the energy of the jet.
 33. The sprinkleraccording to claim 32, wherein the lever arm of said resultant (R) hasminimal dimensions, compatibly with the geometry of the coupling, sothat the overturning torque of said resultant is approximately centeredin an axial region of the joint, proximate to a plurality of gasketswith consequent minimal stresses and local deformations of said gaskets.34. The sprinkler according to claim 33, wherein said at least one elbowcoupling is interchangeable with other ones having different values ofsaid angle (θ) in order to vary the inclination of the jet.
 35. Arotating impact sprinkler, comprising:a tubular body rotatable in adirection about a first axis having a first end in fluid communicationwith a pressurized water pipe and a second end; a nozzle secured to saidsecond end from where a fluid jet exits; an oscillating arm pivotallysecured to said tubular body in a direction substantially perpendicularto said first axis; a deflector pivotally secured to said oscillatingarm such that said deflector pivots about an axis substantially parallelto the first axis of said tubular body; and said deflector is positionedin front of said nozzle distal from said tubular body to periodicallyinteract with said jet to cause rotation of said tubular body.
 36. Therotating impact sprinkler as set forth in claim 35, wherein saiddeflector periodically oscillates between a substantially centralequilibrium position and a second position.
 37. The rotating impactsprinkler as set forth in claim 36, wherein said jet contacts a portionof said deflector having a minimal cross-section when said deflector isin said substantially central equilibrium position.
 38. The rotatingimpact sprinkler as set forth in claim 37, wherein said jet contacts aportion of said deflector having a maximal cross-section when saiddeflector is in said second position.
 39. The rotating impact sprinkleras set forth in claim 38, wherein said second position is at least onelateral abutment position.
 40. The rotating impact sprinkler as setforth in claim 39, wherein said oscillation of the deflector is sosudden as to instantaneously increase the withdrawal of energy from thejet and generate impulsive forces on the deflector and consequently onthe arm regardless of the energy from the jet.